Spin valve heads with a corrosion resistant MnRh exchange layer

A new exchange material, Mn78Rh22, is described, requiring no post-deposition anneal to obtain the antiferromagnetic phase and leading to spin valve sensors with good corrosion resistance, thermal stability up to 225 degrees C, and good exchange coupling characteristics. Potentiodynamic polarization scans performed in a sodium sulfate electrolyte show that Mn78Rh22 films exhibit a good corrosion resistance, comparable to that of Ni81Fe19, Mn80Ir20, and Mn50Ni50 films but with higher corrosion potential. Spin valve structures prepared with this exchange material show an exchange coupling strength (J(ex)) of 0.19 erg/cm(2), The blocking temperature (TB) Of the as-deposited spin valve coupon samples is 235 degrees C, Unshielded sensors with trackwidths W = 4-6 mu m and height h = 1-2 mu m were fabricated. The sensors show well-linearized magnetoresistance (MR) transfer curves, without hysteresis or Barkhausen noise and are thermally stable under consecutive 5 h anneals in vacuum up to 225 degrees C, A.shielded tape head device was fabricated showing a maximum output of 1.8 mV(pp)/mu m, with potential for operating at linear densities near 100 kfci, at which a 580 mu V-pp/mu m output is measured.